Update: I turn my boiler off for the summer (I'm that cheap) and I put it on again about 6 weeks ago and since then not 1 drop in the bucket. Go figure.

In other news, why do I constantly need to bleed the same radiators? I was always told I'll have to bleed them at the start of each season but I find that I need to do it constantly and even stranger, some radiators I never have to bleed no matter what even at the start...